In the past, a synonym for type 1 DM was juvenile onset DM. However, it is now estimated that 10% of youth presenting with DM have type 2 DM. Assessment of autoimmune status, insulin secretion and insulin resistance may be helpful in distinguishing between the two types of DM in youth. In this research project, youth of all ages will have screening tests consisting of antibody panel, C-peptide as a marker of insulin secretion, and IGFBP1 as a marker of insulinization. In older youth, the C-peptide and IGFBP1 response to a standard mixed meal will be measured. In older youth with significant C-peptide response, insulin secretion and resistance will be assessed with an iv glucose tolerance test. These data will be compared to clinical characteristics in the youth, to determine whether autoimmune and biochemical profiles observed in type 1 DM are distinct from that observed in type 2 DM in youth.